For some reason, the bottom left corner in Fence Builder is not being built. I can't find any fault within my code since I copied and pasted from the example code and changed the values around, so it should've worked perfectly.

There are a couple of errors in your code. Remember that each variable, x1, y1, x2, and y2, all stand for a corner. So to help visualize, you could replace the variable with leftBottom and etc. Some of the arrows in the if else statements are pointed the wrong direction, some are >=. Also, you reference the wrong corners sometimes, for example, maybe y1 instead x1 (just an example, may not be true). It's not always +=. Some if statements will require -=. The level seems intimidating at first, but if you realize that + means moving up or right and - means moving left or down, the level becomes a piece of . (It's hard to help with this level without giving away too much.)